From: | Chris Travers <chris(at)metatrontech(dot)com> |
---|---|
To: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Question about the TODO, numerics, and division |
Date: | 2007-03-20 22:11:43 |
Message-ID: | 46005C1F.5040607@metatrontech.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Hi all;
I have been looking at the TODO and have found something that I find
sort of odd and we should probably reconsider:
One of the items under data types is:
* Add NUMERIC division operator that doesn't round?
Currently NUMERIC _rounds_ the result to the specified precision.
This means division can return a result that multiplied by the
divisor is greater than the dividend, e.g. this returns a value > 10:
SELECT (10::numeric(2,0) / 6::numeric(2,0))::numeric(2,0) * 6;
This does not seem to me to be an division op issue but rather a simple
casting mistake. Note that the result of 10/6 is cast as numeric(2,0)
and then multiplied by 6.
The following example shows that the problem is with the query and
casting, not with the division op:
SELECT ((10::numeric(2,0) / 6::numeric(2,0)) * 6)::numeric(2,0);
numeric
---------
10
(1 row)
Am I missing something?
Best Wishes,
Chris Travers
Attachment | Content-Type | Size |
---|---|---|
chris.vcf | text/x-vcard | 171 bytes |
From | Date | Subject | |
---|---|---|---|
Next Message | Gavin Sherry | 2007-03-20 22:36:55 | Re: Bitmapscan changes - Requesting further feedback |
Previous Message | Neil Conway | 2007-03-20 21:19:05 | Re: patch adding new regexp functions |